Orange Micro Terror - A Public Service Announcement ----> Don't Blow Yours up

Good info - thanks !

 

Thanks I mentioned it in the thread I called and they confirmed what you are saying over the phone. I actually bought the little cab at a store that had old stock with the two inputs and was unaware of the change.

 

At least if the Micro Terror catches fire, it will finally achieve some degree of brightness.

 

You won't damage the amp by overheating it. The amp is designed to shut down when it gets too hot.

 

I've noticed a lot of small amps and amp circuit boards from China that state in their specs that you can use whatever ohm speakers you want with their amp/circuit board. Obviously that will only work for so long. Guess they want you to burn up your amp so you'll have to buy another one, and hopefully another one from them.

 

Most modern amp chips are designed to be idiot proof and provide protection against things that can cause failure.

 

GOod to know, appreciated.

 

Have usually run it at 4 ohms, never had any problems. Not Orange cabs though.

 

Looks like you guys are just going to have to start running a quad stack instead of a dual

 

Don't know why I didn't get the previous notification on this thread, but anyway I did read that about the chips awhile back and thought it to be mostly marketing BS. It obviously didn't workout well for the OP and others.

 

What didn't work out for the OP and others? There is no reference to anyone having the amp fail due to running a 4 ohm load.

You can run this amp into 4 ohms if you want. The manufacturer even suggests running the chip in to a 4 ohm load. There is thermal protection to shut it down and keep the chip from failing if it generates too much heat. They even show performance characteristics when running it into a 2 ohm load. STA540, go read the datasheet.

Suggested applications:
2x 38 W into 4 Ω, at 18 V, 1 kHz, 10% THD
2x 24 W into 4 Ω, at 14.4 V, 1 kHz, 10% THD

 

Did you read the OP/1st post? The amp overheated using 4 ohm cabs, now Orange says to use 8 ohm cabs.

 

Yeah, I had one of the original Micro Terrors when they first came out and it definitely said "Min 4 Ohm" on the back.


Sold it, got another one (because they sound awesome and I'm an idiot for selling mine) and the new one says "Min 8 Ohm" on the back.

The first one I had I ran into a 4 ohm 2x12 and one time it did shut down, but didn't catch fire or anything. It was very hot to the touch and that's it. It worked fine after I waited a few minutes. With the new one, I rewired the 2x12 to 16 ohms and it has never shut down so far.

I've never heard of them blowing up though... they probably just shut down and stop working if you use a 4 ohm load and turn them all the way up for too long.

 

Again, neither of those threads contains an account of anyone having the amp fail due to overheating. You can run it into a 4 ohm load and it will not fail from overheating.

 

Here is a pic of the back of a Micro Terror as they are now made:


They obviously either changed something about the design, or decided that a Minimum 8 ohm load is preferred instead of 4 ohms minimum. You -can- use it with a 4ohm load, sure. But if you turn it up all the way it might just shut down for a while when the protection kicks in, that's all. That would be hella annoying to me during a gig though, which is maybe why they changed the type on the back of the amp.

 

They probably just made an error on the size of the heatsink required or it's not getting enough airflow to cool it adequately to run wide open into 4 ohms. Are there apertures on the bottom allowing cool air to enter the enclosure?

Regardless, the death of the Micro Terror has been greatly exaggerated.

 

Correct that the amp didn't fail,....YET. It did overheat due to the ohm mismatch, which is why Orange changed it. Had the amp been used in this manner for a prolonged period, it would eventually fail due to frying the amp board, components and trannys.
Had both the 4 ohm cabs been run in series rather than parallel, there wouldn't have been a problem.
I love the sound that comes from these amps, one day I'll probably get one for myself.

 

The STA540 is a known chip. Used for years in home stereos and some low end car hi-fi. It works just fine at 12V and will deliver the goods. It will shut down safely during overheat or overcurrent. Even if it does fritz, the amp is safe. Owners have been complaining from day one that the amps will sometimes shut down after prolonged use into a 4 Ohm load. There are warning signs. A reduction in volume, an increase in distortion, some cutting in and out. Imagine you're giving your all to a baying crowd and your amp farts out.
That's all. That's it. Switch off, wait a minute or two and off you go again.
Look at the insides of the Micro Terror for clues. Small heatsink. Heatsink inside the chassis. Inadequate ventilation. But, fear not. The STA540 is all but unkillable!.